<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="/test/fun.do" method="post">
    <input type="checkbox" name="orders[0].pids" value="1">1
    <input type="text" name="orders[0].buynums" value="2">number<br>
    <input type="checkbox" name="orders[1].pids" value="3">2
    <input type="text" name="orders[1].buynums" value="4">number<br>
    <input type="checkbox" name="orders[2].pids" value="5">3
    <input type="text" name="orders[2].buynums" >number<br>
    <input type="submit" value="提交">
</form>
</body>
</html>